<p>我希望找到解决办法</p> <p>我有一张带有主键stock的表</p> <pre class="brush:php;toolbar:false;">stkid (pk), name</pre> <p>第二张表（share）</p> <pre class="brush:php;toolbar:false;">price, quantity, stkid (fk)</pre> <p>我运行了这个查询，但它只显示了已经在共享记录中有记录的股票 我希望显示所有股票，即使在共享记录中没有记录</p> <pre class="brush:php;toolbar:false;">select name, 0, sum(price*quantity) / sum(quantity) as avg, sum(quantity) as qty from stock, share where share.stkid = stock.stkid group by (stock.stkid)</pre>

SELECT
  name,
  0,
  sum(price*quantity) / sum(quantity) as avg,
  sum(quantity) as qty
FROM stock
LEFT JOIN share ON share.stkid = stock.stkid
GROUP BY stock.stkid